Arrhythmias are abnormalities in the heart’s rhythm that can lead to complications like palpitations, fainting, stroke, and death. The most common sustained arrhythmia is atrial fibrillation, which affects up to 2% to 9% of people in the United States. This number is expected to increase in the coming years.

Read on to learn more about the different types of arrhythmias and important facts and statistics about atrial fibrillation.

Arrhythmias: Overview

Cardiac arrhythmias are abnormalities in the heartbeat. The heart normally pumps 60-100 times per minute to circulate blood throughout the body. An electrical system inside the heart stimulates the heart muscle to pump with each heartbeat. Abnormalities in the heart’s rhythm can result in extra or missed heartbeats or the heart pumping too fast (tachycardia) or too slow (bradycardia).

The following is a list of the different types of arrhythmias:

  • Atrial fibrillationAtrial flutterAtrial tachycardiaAV-nodal reentrant tachycardia (AVNRT)AV reentrant tachycardia (AVRT)Junctional tachycardiaVentricular tachycardiaVentricular fibrillationTorsade de PointesSick sinus syndromeHeart blockPremature atrial complexes (PACs)Premature ventricular complexes (PVCs)

How Common Are Arrhythmias?

Arrhythmias are common, but some types are more common than others. The most common are premature atrial complexes (PACs) and atrial fibrillation.

Classifying Arrhythmias

Arrhythmias are classified according to where they came from:

Atrial fibrillation affects about 1 in 50 Americans under the age of 65 and about 1 in 10 Americans over age 65.

The incidence of ventricular arrhythmias varies widely. In one study, ventricular arrhythmias occurred in 48 per 100,000 adults (approximately 1 in 2,100 people).

In older adults, ventricular arrhythmias occur in 2-3 out of 100 people who do not have any known risk factors, and in 15-16 in 100 people who have coronary artery disease (CAD).

Arrhythmias by Ethnicity

The prevalence of different types of arrhythmias varies by ethnicity. This might be explained by a combination of disparities in the prevalence of risk factors and the diagnosis of arrhythmias among different ethnicities.

Increasing Prevalence

The prevalence of arrhythmias has increased and is expected to grow because of the aging population in the U.S., and the increase in risk factors for arrhythmias.

Atrial fibrillation is diagnosed more commonly in the Caucasian population, but researchers question whether atrial fibrillation is truly more common in Caucasian adults.

A study found that over a 14-year follow-up period, atrial fibrillation was less commonly diagnosed in Black adults. It showed a 6.6% lower prevalence in Black patients compared to White patients after adjustment for risk factors.

However, when looking at 14-day monitors, the prevalence was not different. This suggests that atrial fibrillation could be underdiagnosed—and not necessarily less common—in Black patients.

Genes may also play a role. One study of genetic mutations that predispose people to sudden cardiac death showed the highest prevalence in the Asian population, followed by Black and Caucasian populations, and the lowest prevalence in the Hispanic population.

Causes and Risk Factors for Arrhythmias

Various problems in the heart’s muscle, structure, and electrical system can cause arrhythmias, including:

  • Lack of blood flow (ischemia), such as from coronary artery disease or heart attack
  • Scar tissue from a prior heart attack
  • Inflammation (myocarditis)
  • Infiltrative heart diseases (e.g., cardiac amyloidosis or cardiac sarcoidosis)
  • Genetic predisposition
  • Congenital heart disease
  • Heart valve problems (e.g., mitral stenosis)
  • Cardiomyopathy or heart failure
  • Alcohol and illicit drugs
  • Certain medications
  • A person’s age
  • Diseases in other organ systems (e.g., lungs and thyroid)

There are also risk factors that we may have control over (called modifiable risk factors) including:

  • Smoking
  • Obesity
  • High blood pressure
  • Heavy alcohol use and binge drinking
  • Drug use
  • Sleep apnea
  • Diabetes
  • Having a sedentary lifestyle

Complications and Mortality Rates of Arrhythmias

Arrhythmia is a broad term that includes a range of abnormal heart rhythms, from harmless extra beats to life-threatening ventricular arrhythmias.

Talking about mortality rates of arrhythmias, in general, is not as helpful as looking at complications and mortality rates for individual arrhythmias. The most serious arrhythmias are discussed below.

Ventricular Arrhythmias & Sudden Cardiac Death

Ventricular arrhythmias are potentially life-threatening arrhythmias that can lead to sudden cardiac death. Premature ventricular complexes (PVCs) are abnormal beats that can be precursors to more serious ventricular arrhythmias like ventricular tachycardia, ventricular fibrillation, and Torsade de Pointes.

Studies have shown that a person with frequent PVCs but otherwise normal heart structure is more likely to develop heart failure and experience higher cardiovascular mortality.

Atrial Fibrillation

Atrial fibrillation is the most common arrhythmia. It’s serious because it increases the risk of mortality and stroke. Mortality rates for atrial fibrillation vary from 1.6% to 4.2% per year.

Sudden Cardiac Death

Ventricular arrhythmias are a major cause of sudden cardiac death. If sudden cardiac death occurs outside of the hospital, the survival rate is about 10%.

Cardiopulmonary resuscitation (CPR) and the use of automated external defibrillators (AEDs) can mean the difference between life and death for someone experiencing sudden cardiac death.

Diagnosis and Early Detection

If you have symptoms of arrhythmia, you should seek medical attention. Your healthcare provider will do an electrocardiogram (ECG). An ECG can diagnose arrhythmias if they are happening at the time the test is done. It can also show hints of a heart problem, like thickened heart walls or scarring from an old heart attack.

Stroke Incidence with Atrial Fibrillation

According to the American Heart Association, atrial fibrillation causes about 1 in 7 strokes, and having atrial fibrillation makes you five times more likely to have a stroke.

A transient heart rhythm problem will not necessarily show up on an ECG. You might be asked to wear a heart monitor for days to weeks to help diagnose an arrhythmia.

Symptoms of Arrhythmia

Symptoms of arrhythmias can include:

Your healthcare provider may refer you to providers who specialize in treating heart disease and arrhythmias, like a heart specialist (cardiologist) or a heart rhythm specialist (electrophysiologist).

Summary

Arrhythmias are abnormalities in the heart’s rhythm. They can range from harmless to life-threatening. Atrial fibrillation is the most common arrhythmia and can be serious, as it increases the risk of stroke and death. Other serious arrhythmias, like ventricular arrhythmias, can result in sudden cardiac death.

Arrhythmias can cause a range of symptoms like brief palpitations and exercise intolerance to loss of consciousness and death. These symptoms can signal underlying problems with your heart or circulatory system. If you have symptoms of arrhythmia, it’s important to have an evaluation by a healthcare provider. They may recommend heart monitoring to diagnose the arrhythmia.

A Word From Verywell

If you are having symptoms you think could be from a heart arrhythmia, call your healthcare provider. Finding out you have an arrhythmia can be scary, but your provider can make sure you get the right treatment.